Mixed forests of pine and deciduous broadleaf trees cover extensive, low-lying hills of Chinese Manchuria and the Amur region of the Russian Far East. The diverse forests that comprise this ecoregion support several species that are severely endangered, including the Siberian tiger and the valuable folk medicine plant, Panax ginseng. While some large forest tracts still remain in remote areas, logging has reduced forest cover in recent years.

Location and General Description

Low hills and mountains of northeast China support some of the most diverse forest ecosystems in Northeast Asia. Two ecoregions occur here. Manchurian mixed forests occupy lower elevation hill areas that extend from the northern part of the Korean Peninsula northward into the Chinese provinces of Jilin and Laioning and still further north into Heilongjiang and the Amur River area of the Russian Far East. This ecoregion encircles the broad river valleys of northeastern China, including the east slope of the Large Hinggan Mountains, the south and west slopes of the Small Hinggan Mountains, and the extensive lower elevation hill regions of the Changbai Mountains at the base of the Korean Peninsula. Changbai Mountains mixed forests include the higher elevation regions where forests are dominated by conifers and the landscape includes alpine meadows and rock slopes.

The climate of this ecoregion is determined by continental influences from interior Asia, predominant during the winter, and monsoon influences from the western Pacific that bring precipitation to this area during the summer. Winters are long, cold and fairly dry with January mean temperatures of around -15° to -20°Celsius (C). Annual precipitation throughout the region is about 500 to 1,000 millimeters (mm) with most rain during the summer and fall.

Manchurian mixed forests are distinguished by a higher incidence of conifers, compared to the deciduous forests to the south. Yim shows that cooling temperatures northward are correlated to a distinct change in the forest vegetation from mainly deciduous broadleaf to mainly coniferous forest vegetation.

Forests at 500 to 1,000 meters (m) elevation include both coniferous and broadleaved species. Conifers include Korean pine (Pinus koraiensis), a straight-trunked pine species that may attain a height of 35 to 40 m. Fir (Abies holophylla), and the spruce, Picea obovata also occur here. P. obovata is a sibling species of Picea abies which is very widespread across northern Eurasia. Broadleaf deciduous (hardwood) species include oaks (Quercus mongolica), ash (Fraxinus mandshurica), Tilia amurensis, birch (Betula schmidtii), Manchurian elm (Ulmus laciniata), maple (Acer spp.), and Manchurian walnut (Juglans mandshurica). Shrubs consist of Manchurian filbert (Corylus mandshurica) and Lespedeza bicolor at lower elevations in the southern region.

Forests on the east slope of the Large Hinggan Mountains have a somewhat different composition. Broadleaf trees include birch (Betula platyphylla), poplar (Populus spp.), willow (Salix rorida) and Mongolian oak (Quercus mongolica). Conifer forests, dominated by the pine, Pinus sylvestris, occur in sandier places.

Siberian tigers (Panthera tigris altaica) historically ranged from the Russian Far East through Manchuria and into the southern part of the Korean Peninsula. While tigers were commonly captured from the Korean Peninsula during the early decades of the twentieth century, there is no record showing the capture of a tiger in South Korea after 1922, and today the species is probably extinct there. It is believed that some tigers may still occur in the Paektusan Mountains of North Korea. The Changbai Mountains of Jilin Province, China also support a few tigers, as do the forests of northern Heilongjiang Province and Amur Oblast in the Russian Far East.

At the beginning of the twentieth century, Panax ginseng grew in the northeast of China and northern areas of the Korean Peninsula. It was not uncommon in the understory of conifer forests within the Manchurian Mixed Forests ecoregion. Its main habitat was mixed conifer (Pinus koraensis, Abies holophylla) and deciduous broadleaf (Quercus mongolica, Tilia mandshurica) forests. In recent decades, this plant has been greatly reduced due to timber harvesting, wildfire, and collection of the root for medicinal purposes. Today P. ginseng is probably extinct in both Chinese Manchuria and on the Korean Peninsula, although it still occurs in the understory of forests in the Primorsky Krai area of the Russian Far East. Urgent measures are needed to restore this economically valuable species and to preserve its genetic potential.

Current Status

The northeastern provinces are one of three regions of China that support substantial timber reserves. Thus, many of the forest stands that comprise this ecoregion have been subject to intensive logging resulting in replacement of late-successional forest by secondary growth and incursion by networks of logging roads that encourage further anthropogenic disturbance.

According to MacKinnon, special conservation measures should be applied to protect the Siberian tiger, including consideration of buffer zones and corridors to link the few surviving animals with adequate living space and wild prey. Moreover, "a public awareness campaign should be mounted to improve local attitudes towards wildlife which is currently seen simply as a free meal.

Justification of Ecoregion Delineation

This ecoregion is concentrated in the mountains of northeastern China but extends north and eastward into Korea and Russia. In China, boundaries were formed according to CVMCC vegetation classes of temperate deciduous oaks (class 14a, Manchurian oak), with spruce-fir forests at higher altitudes. These areas are located within the northern and southern sections of McKinnon’s Changbai Mountains biogeographic region of Northeast China. In Korea, the boundary corresponds to Yim’s northern deciduous broadleaf forest, which roughly covers the central mountain chain (the Taebaik) extending southward. This cool temperate ecoregion is clearly distinguishable from the adjacent Central Korean Deciduous Forest (warm-temperate) because of the transition in floristic composition: the boundary corresponds to the lower limit of subarctic conifers. In Russia, ecoregion boundaries correspond to the southern subzone of the Okhotsk-Manchurian forest province with equal amounts of broadleaf and conifers forests according to Kurnaev’s forest map of the USSR. On Isachenko’s map of USSR landscapes, this area corresponds to the montane deciduous-dark conifer forest in East Siberia.

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